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refactor(css): split syntax into syntax-parser and syntax-printer - #22222
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🦋 Changeset detectedLatest commit: 0143a55 The changes in this PR will be included in the next version bump. This PR includes changesets to release 1 package
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Included review availability: Your plan provides up to 10 included reviews per hour; 5 remain after this review. 📝 WalkthroughWalkthroughThe pull request separates CSS parser references from printer loading, updates affected type and runtime imports, adds deferred printer tests, documents the module split, and declares a webpack patch release. ChangesCSS parser and printer split
Priority: ⬇️ Low Change: Refactor 🚥 Pre-merge checks | ✅ 4✅ Passed checks (4 passed)
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This PR is packaged and the instant preview is available (0e0bd79). Install it locally:
npm i -D webpack@https://pkg.pr.new/webpack@0e0bd79
yarn add -D webpack@https://pkg.pr.new/webpack@0e0bd79
pnpm add -D webpack@https://pkg.pr.new/webpack@0e0bd79 |
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #22222 +/- ##
==========================================
- Coverage 95.02% 93.75% -1.28%
==========================================
Files 753 755 +2
Lines 104909 105039 +130
Branches 32321 32299 -22
==========================================
- Hits 99691 98476 -1215
- Misses 5218 6563 +1345
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Actionable comments posted: 1
- 🪄 Fix CodeRabbit comments on this PR
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Inline comments:
In `@AGENTS.md`:
- Line 746: Update the “algorithm only” guidance in AGENTS.md to apply
specifically to syntax*.js implementation files, while explicitly excluding
public facades and documented generated regions; retain the instruction that new
lookup tables belong in the matching generator.
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📒 Files selected for processing (5)
.changeset/090-css-syntax-parser-printer-split.mdAGENTS.mdlib/css/syntax-parser.jslib/css/syntax-printer.jslib/css/syntax.js
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| - `lib/javascript/data.js` — the Unicode tables the JavaScript parser classifies with, in one module: the run-length identifier ranges the tokenizer decodes on its first non-ASCII code point, and the per-edition `\p{...}` property names only a pattern the engine itself rejected reaches, by `tooling/generate-js-data.js` — which reads both back out of the pinned acorn devDependency, so bumping it is what moves them. | ||
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| The three `syntax.js` files are algorithm only — a new lookup table belongs in the matching generator, not next to the code that reads it. | ||
| Every `syntax*.js` file is algorithm only — a new lookup table belongs in the matching generator, not next to the code that reads it. |
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📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win
🔎 Supported by static analysis
🏁 Script executed:
sed -n ' sixty, eighty p' AGENTS.md
sed -n '735,758p' AGENTS.md
rg -n -C 4 'algorithm only|syntax\*\.js|generated|facade|syntax-printer|syntax\.js' AGENTS.mdRepository: webpack/webpack
Length of output: 27434
🏁 Script executed:
#!/bin/bash
printf '%s\n' '--- AGENTS.md focused ranges ---'
sed -n '68,78p;735,753p' AGENTS.md
printf '%s\n' '--- CSS syntax facade ---'
sed -n '1,220p' lib/css/syntax.js
printf '%s\n' '--- HTML syntax generated-region context ---'
rg -n -C 8 'html entities|generated|lookup|syntax' lib/html/syntax.jsRepository: webpack/webpack
Length of output: 23664
Scope the “algorithm only” rule to implementation files. lib/css/syntax.js is a public facade, and lib/html/syntax.js contains the documented generated html entities region. The current wording covers both cases. Change it to:
Except for public facades and documented generated regions,
syntax*.jsimplementation files are algorithm only — a new lookup table belongs in the matching generator, not next to the code that reads it.
🤖 Prompt for AI Agents
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In `@AGENTS.md` at line 746, Update the “algorithm only” guidance in AGENTS.md to
apply specifically to syntax*.js implementation files, while explicitly
excluding public facades and documented generated regions; retain the
instruction that new lookup tables belong in the matching generator.
After applying the fix, consider running `coderabbit review --agent` for local
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Generated code sizeComparing base (
Read No asset changed size. No runtime gained or lost a runtime module. Built |
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Merging this PR will regress 2 benchmarks
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| Mode | Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|---|
| ❌ | Memory | unit benchmark "js-parser-unit", source 'lodash-es' |
107.7 KB | 272.3 KB | -60.44% |
| ❌ | Simulation | unit benchmark "css-printer-tailwind-unit", minify (flat rules) |
2.4 s | 3.4 s | -28.74% |
| ⚡ | Memory | benchmark "side-effects-reexport", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' |
903.3 KB | 151.4 KB | ×6 |
| ⚡ | Memory | benchmark "common-libs", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' |
901 KB | 563.5 KB | +59.89% |
| ⚡ | Memory | benchmark "many-chunks-commonjs", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' |
278.1 KB | 188.5 KB | +47.58% |
| ⚡ | Memory | benchmark "many-modules-interop-runtime", scenario '{"name":"mode-production","mode":"production"}', measure 'exec' |
20.9 KB | 16.5 KB | +26.64% |
| ⚡ | Memory | benchmark "hmr", scenario '{"name":"mode-development-rebuild","mode":"development","watch":true}' |
966.2 KB | 791.1 KB | +22.13% |
Tip
Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.
Comparing refactor/css-syntax-split (0143a55) with main (ab902ff)2
Footnotes
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6 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩
-
No successful run was found on
main(bb2c8dd) during the generation of this report, so ab902ff was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩
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- 🪄 Fix CodeRabbit comments on this PR
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Inline comments:
In `@lib/util/SourceProcessor.js`:
- Around line 1019-1023: Add focused CSS SourceProcessor tests covering deferred
printer loading: assert walking does not invoke the deferred loader, the first
print invokes it exactly once, and subsequent prints reuse the initialized
printer without invoking the loader again.
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⛔ Files ignored due to path filters (1)
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📒 Files selected for processing (11)
lib/css/CssParser.jslib/css/syntax.jslib/dependencies/CssIcssExportDependency.jslib/html/builtinEmbeddedRenderer.jslib/html/htmlMinify.jslib/html/syntax.jslib/util/SourceProcessor.jstest/helpers/FakeDocument.jstest/specCases/syntaxEquivalence.spectest.jstest/unitCases/CssSyntax.unittest.jstooling/compare-css-tools.js
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The CSS engine and its default printer now live in files of their own, with lib/css/syntax.js keeping the public surface: it loads both, binds SourceProcessor to them and re-exports what it always did. Module state the walk writes and the printer reads moved into one initialized object, so the two files share it without a stale copy; the streaming writer sits in a second one to keep CssPath out of its type. Dependencies run one way — printer to parser, facade to both.
syntax.js now exposes `parser` and `printer` the way lib/javascript's facade does, and every name it published before is a getter onto the half that owns it. Nothing loads until a name is read: requiring the facade loads neither half, and a walk that only fires visitors never loads the printer. SourceProcessor asks for its printer on the first print rather than naming it up front — util/SourceProcessor takes that loader as a third argument and calls it once per process, never per node. In-repo readers that never print (CssParser, CssIcssExportDependency, the html parser's css tokens) now import the parser half directly. `css.syntax.printer` is the printer half now, as in javascript; the print function it holds is `printer.printer`.
The surface test read `parseAStylesheet` and `NodeType`, leaving the other 53 getters unexecuted. Walk every published name instead: each resolves to a defined value, and each one the parser half spells the same way is identical to it.
Deriving the expected names from the facade only checked how many there are: a renamed getter and an alias repointed at another export of the same module both kept the counts at 55 and 49. Spell out the source of each of the 55.
`_anyUnordered`, which the ported seam fix reaches across the cut, was inserted ahead of `_alphaByteText` rather than after it.
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This PR contains the following updates: | Package | Change | [Age](https://docs.renovatebot.com/merge-confidence/) | [Confidence](https://docs.renovatebot.com/merge-confidence/) | |---|---|---|---| | [webpack](https://github.com/webpack/webpack) | [`5.111.1` → `5.112.0`](https://renovatebot.com/diffs/npm/webpack/5.111.1/5.112.0) |  |  | --- >⚠️ **Warning** > > Some dependencies could not be looked up. Check the [Dependency Dashboard](issues/99) for more information. --- ### Release Notes <details> <summary>webpack/webpack (webpack)</summary> ### [`v5.112.0`](https://github.com/webpack/webpack/blob/HEAD/CHANGELOG.md#51120) [Compare Source](webpack/webpack@v5.111.1...v5.112.0) ##### Minor Changes - Apply `plugins` set on a multi-configuration array to the `MultiCompiler`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22702](webpack/webpack#22702)) - Add `optimization.minimize.css.dropOverriddenDeclarations`, dropping a declaration a later one overrides where no target is named. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22175](webpack/webpack#22175)) - Export more plugins under their scope, move eleven loose exports under theirs, deprecate the old, and expose `template.DependencyTemplate`, `module.NullFactory` and `util.makeSerializable`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22261](webpack/webpack#22261)) - Let `util.makeSerializable` take several requests, current one first. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22340](webpack/webpack#22340)) - Emit the source map `scopes` field, so a debugger resolves imported ESM bindings by name. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​21999](webpack/webpack#21999)) - Add `library.entryExports: "all"` to expose the exports of every entry module. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22235](webpack/webpack#22235)) - Recognize a required `const` binding assigned to `exports` as a re-export. (by [@​hai-x](https://github.com/hai-x) in [#​22276](webpack/webpack#22276)) - Accept glob patterns in more path, module and file filter options. (by [@​hai-x](https://github.com/hai-x) in [#​22422](webpack/webpack#22422)) - Bundle a run of inline `<script>` tags into one chunk the page can inline. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22188](webpack/webpack#22188)) - Add `module.parser.javascript.topLevelThis` for classic-script `this` semantics. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22193](webpack/webpack#22193)) - Add `module.parser.html.chunkName` and a `webpackChunkName` comment for tags. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22200](webpack/webpack#22200)) - Add `include`/`exclude` version and request filters to shared modules. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22297](webpack/webpack#22297)) - Keep module side-effect information in ESM output as PURE annotations. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​21789](webpack/webpack#21789)) - Add `optimization.splitChunks.dedupDepth` to discover chunk intersections. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22240](webpack/webpack#22240)) - Add `optimization.minimizeOptions.json`, on by default with `futureDefaults`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22286](webpack/webpack#22286)) - Add `SSRManifestPlugin` and fix server-rendered CSS collection and adoption. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​21913](webpack/webpack#21913)) - Add an `ignore` hook to `output.copy` and keep unfollowed `from` symlinks. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22216](webpack/webpack#22216)) - Add `optimization.minimize.css.convertApproximateColors`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22157](webpack/webpack#22157)) - Add XML parsing and SVG/XML minification with data URLs and attribute sorting. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22269](webpack/webpack#22269)) - Extract CSS/HTML license comments like JS and safely shorten CSS gradients. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22408](webpack/webpack#22408)) - Resolve an async `DefinePlugin.runtimeValue` over an async `beforeParse` hook. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22210](webpack/webpack#22210)) - Add CSS `customMedia`/`customSelectors` minimize options; resolve chained names. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22360](webpack/webpack#22360)) - Rename the `Harmony*` names to `ESM*` and deprecate the old spellings. (by [@​hai-x](https://github.com/hai-x) in [#​22283](webpack/webpack#22283)) - Reduce `css.syntax`/`html.syntax` to `parser`, `printer`, `SourceProcessor` with one node path. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22233](webpack/webpack#22233)) - Add a JavaScript `SyntaxTree` read like the CSS one, and `toEstreeObject`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22608](webpack/webpack#22608)) - Fix minified code that threw, and add `pure_conversions` and `pure_heritage`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22473](webpack/webpack#22473)) - Shorten more CSS values and selectors, fold longhands, order declarations and gather layer blocks. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22442](webpack/webpack#22442)) - Add `optimization.minimize.css.charset`; `false` drops `@charset` for UTF-8 CSS. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22632](webpack/webpack#22632)) ##### Patch Changes - Join rules a gathered `@layer` leaves adjacent, and an at-rule with a later one (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22204](webpack/webpack#22204)) stating the same condition; read what a condition declares. - Read escaped CSS names and functions as spelled, and minify them unescaped. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22262](webpack/webpack#22262)) - Minify JavaScript, CSS and HTML assets whose names carry a `#fragment`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22277](webpack/webpack#22277)) - Require `minimizer-webpack-plugin` 5.12, so inline scripts in HTML minify again. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22296](webpack/webpack#22296)) - Minify the attributes of an HTML tag without rewriting the template in it. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22166](webpack/webpack#22166)) - Order joined at-rule selector lists and gather a repeated large `@layer` block. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22224](webpack/webpack#22224)) - Preserve case-sensitive template identifiers when minifying HTML tag attributes. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22177](webpack/webpack#22177)) - Match Acorn's strict directives, Unicode identifiers and expression validation. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22185](webpack/webpack#22185)) - Skip concatenating modules when `optimization.providedExports` is disabled. (by [@​hai-x](https://github.com/hai-x) in [#​22410](webpack/webpack#22410)) - Join rules a nesting lowering or duplicate drop left for a second pass. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22268](webpack/webpack#22268)) - Write U+00A0 in a minified HTML attribute as the character, not ` `. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22208](webpack/webpack#22208)) - Escape a foreign `<script>` or `<style>` body, which is character data. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22233](webpack/webpack#22233)) - Name the runtime module whose generation fails while hashing. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22203](webpack/webpack#22203)) - Rebuild a module in watch when its missing unused dependencies swap. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22693](webpack/webpack#22693)) - Rebuild in watch mode when a file is deleted while a build is running. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22650](webpack/webpack#22650)) - Take out the declaration a lowered shorthand writes over, which its source spelling made look like a fallback. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22270](webpack/webpack#22270)) - Read a foreign `<script>` or `<style>` body as character data, not as raw text. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22258](webpack/webpack#22258)) - Keep an inline `<style>` body as written when rebuilding a page webpack emitted. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22265](webpack/webpack#22265)) - Fix minified HTML for `style` spellings, CSS quotes, `<noscript>` and a BOM. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22370](webpack/webpack#22370)) - Record a build dependency required through a spread on Bun. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22230](webpack/webpack#22230)) - Write a nested selector opening on a combinator against its parent the way the printer writes one. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22271](webpack/webpack#22271)) - Fix missing async stylesheets with a shared runtime. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22659](webpack/webpack#22659)) - Support deferred imports introduced by hot updates. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22668](webpack/webpack#22668)) - Fix trailing commas in `require.resolve()` and `require.resolveWeak()` calls. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22658](webpack/webpack#22658)) - Keep regular expressions, functions and plugins distinct in resolver caches. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22667](webpack/webpack#22667)) - Order the list a lowered nested selector lands in on what is written, not on what was. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22287](webpack/webpack#22287)) - Hoist a vendor-prefixed nested rule for a target that reads no nesting. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22308](webpack/webpack#22308)) - Name a hoisted nested rule in the dark-scheme copy it writes. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22318](webpack/webpack#22318)) - Minify data: URL payloads in HTML attributes and `new URL`, and web manifests. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22300](webpack/webpack#22300)) - fold a fallback's colors over the author's arguments, and print with (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22314](webpack/webpack#22314)) `recurseBlocks: false` rather than throwing - Read a regular expression repeating a capture group name in linear time. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22187](webpack/webpack#22187)) - Make lazy barrels defer import declarations and keep no deferral across compilations. (by [@​hai-x](https://github.com/hai-x) in [#​22359](webpack/webpack#22359)) - Invalidate unaffected caches when connection activity or async status changes. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22431](webpack/webpack#22431)) - Order concatenated re-exports deterministically when their source order ties. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22697](webpack/webpack#22697)) - Regenerate a module's exports when a require() cycle forms or breaks around it. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22644](webpack/webpack#22644)) - Recompute re-exports, code and warnings when a module goes missing or returns. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22432](webpack/webpack#22432)) - Preserve loader resolution dependencies across cached rebuilds. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22430](webpack/webpack#22430)) - Read unwatched changes afresh and wait for restarted watch compilers to finish. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22646](webpack/webpack#22646)) - Parse loader output for `.wasm` as JavaScript when async wasm is auto-enabled. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22556](webpack/webpack#22556)) - Remove modules an async chunk inherits from a named parent chunk grown later. (by [@​hai-x](https://github.com/hai-x) in [#​22555](webpack/webpack#22555)) - Fix JavaScript minifier crashes, altered behavior, lost comments, unparsable output and null source map sources, including parameter aliases, ESTree trees and preserved names, and stop it writing into the caller's parse options. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22352](webpack/webpack#22352)) - Preserve the source phase of dynamic WebAssembly import contexts. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22604](webpack/webpack#22604)) - Await every async entry before resolving an ESM library import. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22617](webpack/webpack#22617)) - Keep unknown `import.meta` properties per module, alike for aliases and direct use. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22618](webpack/webpack#22618)) - Return WebAssembly modules directly from eager and weak source imports. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22606](webpack/webpack#22606)) - Handle missing ESM hot update manifests in Node.js without failing HMR checks. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22613](webpack/webpack#22613)) - Speed up JavaScript parsing: comment lookup, the tokenizer and the grammar. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22179](webpack/webpack#22179)) - Name a core module external by its key whichever spelling the code uses. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22565](webpack/webpack#22565)) - Prefix and drop 2009 flexbox names, keeping them where a box lays out by them. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22320](webpack/webpack#22320)) - Keep `initial` where Gecko or WebKit reads the property's keyword apart. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22176](webpack/webpack#22176)) - Fold `calc()` as lightningcss does, keeping it where a bare value is refused. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22205](webpack/webpack#22205)) - Keep a `color-mix()` whose hue rests on a gray's conversion residue. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22198](webpack/webpack#22198)) - Keep a shorthand's initial keyword where it parts two keywords of another slot. (by [@​dependabot](https://github.com/apps/dependabot) in [#​22518](webpack/webpack#22518)) - Group `lib/` and `lib/dependencies/` sources into directories. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22118](webpack/webpack#22118)) - Treat a browserslist target given at a bare major version (e.g. `safari 10`) as `<major>.0` when a feature's first supported version is a `[major, minor]` pair, so it is no longer reported as unsupported. (by [@​Eshiv-Pandey](https://github.com/Eshiv-Pandey) in [#​22280](webpack/webpack#22280)) - Keep the last HMR update with `output.clean`; stop rechecking removed files. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22339](webpack/webpack#22339)) - Read and print a CSS backslash as the spec does, and a NUL as U+FFFD. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22201](webpack/webpack#22201)) - Make minified CSS and HTML stable on a second pass, even for truncated input. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22290](webpack/webpack#22290)) - Minify a merged `<style>` run as one sheet, closing each where its input ended. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22302](webpack/webpack#22302)) - Minify JavaScript with webpack's printer under `futureDefaults`, `terser` otherwise. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22217](webpack/webpack#22217)) - Preserve `wrappedContextRegExp` flags when rebuilding context request matchers. (by [@​Eshiv-Pandey](https://github.com/Eshiv-Pandey) in [#​22303](webpack/webpack#22303)) - Minify CSS `@supports`, `@import` and `@custom-media` conditions, and exponent numbers. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22347](webpack/webpack#22347)) - Fold unitless `hsl()`/`hwb()` channels, and only where the separators are valid. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22242](webpack/webpack#22242)) - Split `@value` imports on the `from` keyword, not a substring in the path. (by [@​Eshiv-Pandey](https://github.com/Eshiv-Pandey) in [#​22306](webpack/webpack#22306)) - Destructure a dotted `DefinePlugin` key whose value is falsy or a runtimeValue. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22215](webpack/webpack#22215)) - Make `Stats.hasErrors()` read errors through the `processErrors` hook (via `getErrors()`), matching `hasWarnings()`, so a plugin that filters errors out of the hook is no longer contradicted by `hasErrors()`. (by [@​Eshiv-Pandey](https://github.com/Eshiv-Pandey) in [#​22281](webpack/webpack#22281)) - Allow wrapping an external concatenated module, now asked of the module itself, and re-exporting a JSON or asset `default` as a namespace object. (by [@​hai-x](https://github.com/hai-x) in [#​22226](webpack/webpack#22226)) - Match `urlHints` rules written with `and`, `or`, `not` and `glob` conditions; profile hook map taps, such as resolver and parser hooks, in `ProfilingPlugin`; report `import.meta` option errors inside `require.ensure` callbacks, not crash; and replace `any`, `object` and `Function` with precise types in the type definitions. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22681](webpack/webpack#22681)) - Reduce CSS and HTML build time and memory allocation. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22135](webpack/webpack#22135)) - Reuse free names instead of re-parsing modules for the entry IIFE rename. (by [@​hai-x](https://github.com/hai-x) in [#​22206](webpack/webpack#22206)) - Release each module's ast once scope-analysed, and encode each export path once. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22241](webpack/webpack#22241)) - Export a module library entry's default expression as its own binding, and keep (by [@​hai-x](https://github.com/hai-x) in [#​22227](webpack/webpack#22227)) the export helpers where the entry is not inlined. - Give a wrapped concatenated body the same function header as a module factory. (by [@​hai-x](https://github.com/hai-x) in [#​22254](webpack/webpack#22254)) - Skip reading every asset when no content hash is named. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22256](webpack/webpack#22256)) - Cut graph, cached set, lazy barrel and ESM import memory and allocations. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22289](webpack/webpack#22289)) - Stop a module source from being held as both a string and a buffer. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22294](webpack/webpack#22294)) - Read the browserslist data and options schema only when a build needs them. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22324](webpack/webpack#22324)) - Release the eval devtool's cached module sources after wrapping them. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22358](webpack/webpack#22358)) - Release the rendered module sources after emitting the chunks. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22365](webpack/webpack#22365)) - Cut the peak memory and time of minifying through webpack's printer. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22368](webpack/webpack#22368)) - Shrink minified JS: unwrap IIFEs, fold calls, drop dead code, split arrays. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22393](webpack/webpack#22393)) - Cut JavaScript minifier time and memory; keep token positions in large inputs. (by [@​bjohansebas](https://github.com/bjohansebas) in [#​22329](webpack/webpack#22329)) - Keep the `calc()` around a `steps()` count `jump-none` would reject bare. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22168](webpack/webpack#22168)) - Split the CSS syntax module into a parser file and a printer file. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22222](webpack/webpack#22222)) - Update enhanced-resolve to 5.26.0. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22358](webpack/webpack#22358)) - Update watchpack to 2.6.1. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22670](webpack/webpack#22670)) - Split the HTML syntax module into a parser file and a printer file. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22223](webpack/webpack#22223)) - Rename classes in `lib/` so each says what it does and no two share a name. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22361](webpack/webpack#22361)) - Keep the remote fallback index aligned with registered container externals when an `internal ` external precedes a real one. (by [@​Eshiv-Pandey](https://github.com/Eshiv-Pandey) in [#​22362](webpack/webpack#22362)) - Stop a minified inlined chunk leaving a doubled `;` in its `<script>`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22370](webpack/webpack#22370)) - Stop `mergeDistantRules` mangling rules or reordering `all`, and merge more. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22370](webpack/webpack#22370)) - Minify by parsing with webpack's own parser rather than terser's. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22397](webpack/webpack#22397)) - Read JavaScript with webpack's parser alone when minifying, refusing early errors. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22397](webpack/webpack#22397)) - Parse an `assert(...)` call after an import with no semicolon, and a regular expression after `yield` in a generator method. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22406](webpack/webpack#22406)) - Keep the private names a direct `eval` reads when mangling. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22412](webpack/webpack#22412)) - Keep a class dropped for its effects where they read a private name it declares. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22421](webpack/webpack#22421)) - Parenthesize the right side of a private `in`, a `yield`, `await`, private `in` or optional chain tagging a template, and a `let` or `async` starting a statement or loop head, where the minifier printed code that no longer parsed or read otherwise. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22437](webpack/webpack#22437)) - Keep a name a parameter list or catch parameter reads from resolving to what the function body or catch block declares, which the minifier renamed or dropped as unused. (by [@​aryanraj45](https://github.com/aryanraj45) in [#​22439](webpack/webpack#22439)) - Scope and export a CSS Modules `@value` the same way whether local or imported. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22443](webpack/webpack#22443)) - Keep CSS `border: none` and gradient fallbacks for units a target cannot read. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22567](webpack/webpack#22567)) - Keep minified CSS safe for older browsers; drop dead fallbacks and overrides. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22696](webpack/webpack#22696)) - Keep CSS rules apart from a neighbor whose selector no browser parses. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22634](webpack/webpack#22634)) - Keep an `:nth-*()` argument with a space after its sign as written. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22700](webpack/webpack#22700)) - Keep minified CSS readable by browsers the compat data does not cover. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22701](webpack/webpack#22701)) - Keep a module its chunk still needs after `compilation.rebuildModule()`. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22705](webpack/webpack#22705)) - Keep a CSS rule nested under a selector opening on a combinator when lowering. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22707](webpack/webpack#22707)) - Use module paths for webpack's built-in minimizers so parallel minification can load them directly in workers instead of serializing their function sources. (by [@​xiaoxiaojx](https://github.com/xiaoxiaojx) in [#​22309](webpack/webpack#22309)) - Keep stats from an earlier build readable after a later build no longer has one of their modules. (by [@​alexander-akait](https://github.com/alexander-akait) in [#​22695](webpack/webpack#22695)) </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - "before 9am on tuesday" - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate CLI](https://github.com/renovatebot/renovate). <!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0NC4xNjcuMCIsInVwZGF0ZWRJblZlciI6IjQ0LjE2Ny4wIiwidGFyZ2V0QnJhbmNoIjoiZGV2ZWxvcCIsImxhYmVscyI6WyJkZXBlbmRlbmNpZXMiLCJyZW5vdmF0ZSJdfQ==--> Reviewed-on: https://code.futo.org/harbor/harbor/pulls/1941 Reviewed-by: Mark Harding <mark@futo.org>
Summary
lib/css/syntax.jswas one 19k-line file holding both the engine and its printer. It now names its two halves the wayjavascriptdoes since #22217:syntax-parser.jsreads a stylesheet,syntax-printer.jswrites one back out, andsyntax.jskeeps the public surface — it bindsSourceProcessorto both and re-exports every name it always did, so nothing a caller imports changes.The one thing that could not simply move is the module state the walk writes and the printer reads: a
requirecopies a binding's value, so a reassigned array would go stale across the cut. Those bindings are now fields of one object initialized in full (per the guide's "Keep instance shapes stable"), with the streaming writer in a second one soCssPathstays out of its type. Dependencies run one way: printer → parser, facade → both.What kind of change does this PR introduce?
refactor — no behaviour change; the minifier emits byte-identical output.
Did you add tests for your changes?
No new cases: the existing suites cover it —
CssSyntax.unittest.js,CssValueSyntax.unittest.js,SourceProcessor.unittest.jsand thecssconfigCases. Output was also checked directly, byte for byte, over thebenchmark:css-toolsstylesheets.Does this PR introduce a breaking change?
No.
If relevant, what needs to be documented once your changes are merged or what have you already documented?
Done in this PR: the
AGENTS.mdprose that namedlib/css/syntax.jsfor things now in one half or the other.Use of AI
AI (Claude Code) was used. The split itself was produced by a script rather than by hand: it resolves every binding with
eslint-scope, puts a declaration on the printer's side only when nothing the engine reaches needs it, and closes each side under its own references — so the cut is derived from the dependency graph, not from where a function happened to sit. Fullyarn lint, the CSS unit suites and thecssconfigCaseswere run locally, and both halves were checked to emit byte-identical output.Generated by Claude Code
Summary by CodeRabbit
Performance
Documentation
Chores